Swap Two Variables Without Using a Temp Variable

Favorite interview question for unimaginative interviewers everywhere. Two basics solutions

1.Xor trick

the typical solution is three bitwise exclusive or (xor) operations in succession:

var a = 10, b = 20;

a = a ^ b;
b = a ^ b;
a = a ^ b;

2. Simple math

var a = 10, b = 20;

a = a + b;
b = a - b;
a = a - b;

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